Synthesis, crystal structures, and properties of copper complexes with tripodal ligands and azide anion

Abstract

Two new CuII complexes, (CuL1N3)ClO4 (1) and (CuL2N3)ClO4 (2), have been synthesized and characterized in the presence of NaN3, where L1 = tris[2-(6-methylpyridyl)methyl]amine and L2 = tris[(3,5-dimethylpyrazol-l-yl)methyl]amine, and their crystal structures have been determined by X-ray diffraction methods. Compound 1 crystallizes in the triclinic space group P−1, with a = 8.258(2) A, b = 11.481(2) A, c = 14.158(3) A, α = 72.30(3)°, β = 79.05(3)°, γ = 86.08(3)°, V = 1255.4(5) A3. Compound 2 crystallizes in the monoclinic space group C2/c, with a = 26.752(2) A, b = 10.561(2) A, c = 21.059(4) A, β = 120.51(3)°, V = 5126(3) A3. In both compounds, each CuII center is in a distorted trigonal–bipyramidal coordinated environment with four nitrogen atoms from the tripodal ligand and one nitrogen atom from the azide group. The coordination geometry around CuII center of 1 is axially compressed trigonal bipyramid, while that of 2 is an axially elongated trigonal bipyramid. The coordinated azide group is in the axial site in both complexes. A quasi-dimeric structure of 1 has been formed in the unit cell through hydrogen bonding. The electronic spectra of two complexes in solution have been further studied by UV–vis technique, and the coordination properties have been discussed.